Awaking N-hyperfine couplings in charged yttrium nitride endohedral fullerenes

Abstract

The electron spin properties of endohedral metallofullerene molecules have broad potential applications in quantum information and magnetic induction systems due to the high stability and sensitivity. Herein, we synthesized a series of Y₃N@C_2n (n = 40–44) molecules and studied the hyperfine structures of their anion radicals via ESR measurements and DFT calculations. N-Hyperfine couplings were clearly observed in the ESR spectra of charged Y₃N@C₈₀ and Y₃N@C₈₆ anion radicals, which are not found in the other metallofullerenes. The ESR results revealed size-dependent spin distributions and hyperfine structures, which are sensitive to subtle changes in the carbon cage and the configuration of the yttrium nitride cluster. BOMD cluster trajectories simulations indicated that the Y₃N cluster almost rotates freely in neutral Y₃N@C₈₀ but there is a certain degree of limitation in the Y₃N@C₈₀ anion.